WebAuthn Passwordless Authentication

// WebAuthn Hello World - Basic Passwordless Authentication
// Simple implementation of registration and authentication

class WebAuthnHelloWorld {
  constructor() {
    this.challenges = new Map() // Store challenges for verification
    this.credentials = new Map() // In-memory credential storage (use DB in production)
  }

  // Generate random challenge
  generateChallenge() {
    const array = new Uint8Array(32)
    crypto.getRandomValues(array)
    return this.arrayBufferToBase64URL(array.buffer)
  }

  // Convert ArrayBuffer to Base64URL
  arrayBufferToBase64URL(buffer) {
    return btoa(String.fromCharCode(...new Uint8Array(buffer)))
      .replace(/\+/g, '-')
      .replace(/\//g, '_')
      .replace(/=/g, '')
  }

  // Convert Base64URL to ArrayBuffer
  base64URLToArrayBuffer(base64url) {
    const base64 = base64url.replace(/-/g, '+').replace(/_/g, '/')
    const padded = base64 + '='.repeat((4 - (base64.length % 4)) % 4)
    return Uint8Array.from(atob(padded), c => c.charCodeAt(0)).buffer
  }

  // Register new credential
  async register(username, displayName = username) {
    try {
      // Generate challenge
      const challenge = this.generateChallenge()
      this.challenges.set(username, challenge)

      // Create credential creation options
      const credentialCreationOptions = {
        challenge: this.base64URLToArrayBuffer(challenge),
        rp: {
          name: "WebAuthn Demo",
          id: window.location.hostname
        },
        user: {
          id: this.base64URLToArrayBuffer(btoa(username)),
          name: username,
          displayName: displayName
        },
        pubKeyCredParams: [
          { alg: -7, type: "public-key" },   // ES256
          { alg: -257, type: "public-key" }  // RS256
        ],
        authenticatorSelection: {
          authenticatorAttachment: "platform", // Use device built-in authenticator
          userVerification: "required"
        },
        timeout: 60000,
        attestation: "direct"
      }

      console.log('Creating credential with options:', credentialCreationOptions)

      // Create credential
      const credential = await navigator.credentials.create({
        publicKey: credentialCreationOptions
      })

      if (!credential) {
        throw new Error('Credential creation failed')
      }

      // Store credential (in production, save to database)
      const credentialData = {
        id: this.arrayBufferToBase64URL(credential.rawId),
        type: credential.type,
        response: {
          attestationObject: this.arrayBufferToBase64URL(credential.response.attestationObject),
          clientDataJSON: this.arrayBufferToBase64URL(credential.response.clientDataJSON)
        }
      }

      this.credentials.set(username, credentialData)

      console.log('Credential registered successfully:', {
        username,
        credentialId: credentialData.id
      })

      return {
        success: true,
        credentialId: credentialData.id,
        message: 'Registration successful!'
      }

    } catch (error) {
      console.error('Registration error:', error)
      return {
        success: false,
        error: error.message || 'Registration failed'
      }
    }
  }

  // Authenticate user
  async authenticate(username) {
    try {
      // Get stored credential
      const storedCredential = this.credentials.get(username)
      if (!storedCredential) {
        throw new Error('No credential found for this user')
      }

      // Generate challenge
      const challenge = this.generateChallenge()
      this.challenges.set(username, challenge)

      // Create assertion options
      const assertionOptions = {
        challenge: this.base64URLToArrayBuffer(challenge),
        allowCredentials: [{
          id: this.base64URLToArrayBuffer(storedCredential.id),
          type: storedCredential.type,
          transports: ['internal', 'usb', 'ble', 'nfc']
        }],
        userVerification: "required",
        timeout: 60000
      }

      console.log('Authenticating with options:', assertionOptions)

      // Get assertion
      const assertion = await navigator.credentials.get({
        publicKey: assertionOptions
      })

      if (!assertion) {
        throw new Error('Authentication failed')
      }

      // Verify assertion (simplified - in production, verify cryptographic signature)
      const assertionData = {
        credentialId: this.arrayBufferToBase64URL(assertion.rawId),
        response: {
          authenticatorData: this.arrayBufferToBase64URL(assertion.response.authenticatorData),
          clientDataJSON: this.arrayBufferToBase64URL(assertion.response.clientDataJSON),
          signature: this.arrayBufferToBase64URL(assertion.response.signature),
          userHandle: assertion.response.userHandle ?
            this.arrayBufferToBase64URL(assertion.response.userHandle) : null
        }
      }

      console.log('Authentication successful:', {
        username,
        credentialId: assertionData.credentialId
      })

      return {
        success: true,
        credentialId: assertionData.credentialId,
        message: 'Authentication successful!'
      }

    } catch (error) {
      console.error('Authentication error:', error)
      return {
        success: false,
        error: error.message || 'Authentication failed'
      }
    }
  }

  // Check if WebAuthn is supported
  static isSupported() {
    return !!(navigator.credentials && navigator.credentials.create && navigator.credentials.get)
  }

  // Check if platform authenticator is available
  static async isPlatformAuthenticatorAvailable() {
    if (!this.isSupported()) return false

    try {
      const available = await PublicKeyCredential.isUserVerifyingPlatformAuthenticatorAvailable()
      return available
    } catch (error) {
      console.warn('Error checking platform authenticator:', error)
      return false
    }
  }
}

// HTML UI Example
// <!DOCTYPE html>
// <html>
// <head>
//   <title>WebAuthn Hello World</title>
//   <style>
//     body {
//       font-family: system-ui, -apple-system, sans-serif;
//       max-width: 500px;
//       margin: 50px auto;
//       padding: 20px;
//       background: #f5f5f5;
//     }
//     .container {
//       background: white;
//       padding: 30px;
//       border-radius: 10px;
//       box-shadow: 0 2px 10px rgba(0,0,0,0.1);
//     }
//     h1 {
//       text-align: center;
//       color: #333;
//       margin-bottom: 30px;
//     }
//     .form-group {
//       margin-bottom: 20px;
//     }
//     label {
//       display: block;
//       margin-bottom: 5px;
//       font-weight: 500;
//       color: #555;
//     }
//     input {
//       width: 100%;
//       padding: 12px;
//       border: 1px solid #ddd;
//       border-radius: 5px;
//       font-size: 16px;
//       box-sizing: border-box;
//     }
//     button {
//       width: 100%;
//       padding: 12px;
//       background: #007AFF;
//       color: white;
//       border: none;
//       border-radius: 5px;
//       font-size: 16px;
//       cursor: pointer;
//       margin-bottom: 10px;
//     }
//     button:hover {
//       background: #0056b3;
//     }
//     button:disabled {
//       background: #ccc;
//       cursor: not-allowed;
//     }
//     .status {
//       padding: 15px;
//       border-radius: 5px;
//       margin-top: 20px;
//       text-align: center;
//     }
//     .success {
//       background: #d4edda;
//       color: #155724;
//       border: 1px solid #c3e6cb;
//     }
//     .error {
//       background: #f8d7da;
//       color: #721c24;
//       border: 1px solid #f5c6cb;
//     }
//     .info {
//       background: #d1ecf1;
//       color: #0c5460;
//       border: 1px solid #bee5eb;
//     }
//   </style>
// </head>
// <body>
//   <div class="container">
//     <h1>🔐 WebAuthn Hello World</h1>

//     <div class="form-group">
//       <label for="username">Username:</label>
//       <input type="text" id="username" placeholder="Enter your username" value="alice">
//     </div>

//     <button id="registerBtn" onclick="register()">Register New Credential</button>
//     <button id="authenticateBtn" onclick="authenticate()">Sign In</button>

//     <div id="status" class="status info">
//       Click "Register" to create a new credential, then "Sign In" to authenticate
//     </div>
//   </div>

//   <script src="webauthn-hello-world.js"></script>
//   <script>
//     const webauthn = new WebAuthnHelloWorld()

//     // Check browser support
//     if (!WebAuthnHelloWorld.isSupported()) {
//       updateStatus('WebAuthn is not supported in this browser', 'error')
//       document.getElementById('registerBtn').disabled = true
//       document.getElementById('authenticateBtn').disabled = true
//     }

//     async function register() {
//       const username = document.getElementById('username').value.trim()
//       if (!username) {
//         updateStatus('Please enter a username', 'error')
//         return
//       }

//       updateStatus('Creating credential...', 'info')
//       disableButtons(true)

//       try {
//         const result = await webauthn.register(username)
//         if (result.success) {
//           updateStatus(`✅ ${result.message} (ID: ${result.credentialId})`, 'success')
//         } else {
//           updateStatus(`❌ Registration failed: ${result.error}`, 'error')
//         }
//       } catch (error) {
//         updateStatus(`❌ Registration error: ${error.message}`, 'error')
//       } finally {
//         disableButtons(false)
//       }
//     }

//     async function authenticate() {
//       const username = document.getElementById('username').value.trim()
//       if (!username) {
//         updateStatus('Please enter a username', 'error')
//         return
//       }

//       updateStatus('Authenticating...', 'info')
//       disableButtons(true)

//       try {
//         const result = await webauthn.authenticate(username)
//         if (result.success) {
//           updateStatus(`✅ ${result.message} (ID: ${result.credentialId})`, 'success')
//           // Redirect to dashboard on success
//           setTimeout(() => {
//             updateStatus('🎉 Authentication successful! Redirecting...', 'success')
//           }, 2000)
//         } else {
//           updateStatus(`❌ Authentication failed: ${result.error}`, 'error')
//         }
//       } catch (error) {
//         updateStatus(`❌ Authentication error: ${error.message}`, 'error')
//       } finally {
//         disableButtons(false)
//       }
//     }

//     function updateStatus(message, type) {
//       const statusEl = document.getElementById('status')
//       statusEl.textContent = message
//       statusEl.className = `status ${type}`
//     }

//     function disableButtons(disabled) {
//       document.getElementById('registerBtn').disabled = disabled
//       document.getElementById('authenticateBtn').disabled = disabled
//     }

//     // Check platform authenticator availability
//     (async () => {
//       const isAvailable = await WebAuthnHelloWorld.isPlatformAuthenticatorAvailable()
//       if (isAvailable) {
//         console.log('✅ Platform authenticator (biometric) is available')
//       } else {
//         console.log('ℹ️ Platform authenticator not available, but you can use security keys')
//       }
//     })()
//   </script>
// </body>
// </html>

// Usage example:
// const webauthn = new WebAuthnHelloWorld()
//
// // Register a new user
// webauthn.register('alice', 'Alice Smith')
//   .then(result => console.log(result))
//
// // Authenticate existing user
// webauthn.authenticate('alice')
//   .then(result => console.log(result))

export default WebAuthnHelloWorld

// WebAuthn Passkeys Manager - Complete Passwordless Authentication System
// Multiple device support, backup options, and enterprise features

interface PasskeyCredential {
  id: string
  name: string
  createdAt: Date
  lastUsedAt?: Date
  deviceType: 'platform' | 'cross-platform'
  userHandle: string
  publicKey: string
  counter: number
  transports: string[]
  backupEligible: boolean
  backupState: boolean
}

interface UserAccount {
  id: string
  username: string
  email: string
  displayName: string
  passkeys: PasskeyCredential[]
  createdAt: Date
  lastLoginAt?: Date
  mfaEnabled: boolean
}

class PasskeysManager {
  private db: IDBDatabase | null = null
  private readonly DB_NAME = 'PasskeysManagerDB'
  private readonly DB_VERSION = 1
  private readonly STORE_NAME = 'users'

  constructor() {
    this.initDB()
  }

  // Initialize IndexedDB for credential storage
  private async initDB(): Promise<void> {
    return new Promise((resolve, reject) => {
      const request = indexedDB.open(this.DB_NAME, this.DB_VERSION)

      request.onerror = () => reject(request.error)
      request.onsuccess = () => {
        this.db = request.result
        resolve()
      }

      request.onupgradeneeded = (event) => {
        const db = (event.target as IDBOpenDBRequest).result

        if (!db.objectStoreNames.contains(this.STORE_NAME)) {
          const store = db.createObjectStore(this.STORE_NAME, { keyPath: 'id' })
          store.createIndex('username', 'username', { unique: true })
          store.createIndex('email', 'email', { unique: true })
        }
      }
    })
  }

  // Generate secure random challenge
  private generateChallenge(): string {
    const array = new Uint8Array(32)
    crypto.getRandomValues(array)
    return Array.from(array, byte => byte.toString(16).padStart(2, '0')).join('')
  }

  // Convert ArrayBuffer to Base64URL
  private arrayBufferToBase64URL(buffer: ArrayBuffer): string {
    return btoa(String.fromCharCode(...new Uint8Array(buffer)))
      .replace(/\+/g, '-')
      .replace(/\//g, '_')
      .replace(/=/g, '')
  }

  // Convert Base64URL to ArrayBuffer
  private base64URLToArrayBuffer(base64url: string): ArrayBuffer {
    return Uint8Array.from(atob(base64url.replace(/-/g, '+').replace(/_/g, '/')), c => c.charCodeAt(0)).buffer
  }

  // Generate unique user ID
  private generateUserId(): string {
    return this.arrayBufferToBase64URL(crypto.getRandomValues(new Uint8Array(16)))
  }

  // Create new user account
  async createUser(username: string, email: string, displayName: string): Promise<UserAccount> {
    if (!this.db) throw new Error('Database not initialized')

    // Check if user already exists
    const existingUser = await this.getUserByUsername(username)
    if (existingUser) {
      throw new Error('User already exists')
    }

    const user: UserAccount = {
      id: this.generateUserId(),
      username,
      email,
      displayName,
      passkeys: [],
      createdAt: new Date(),
      mfaEnabled: false
    }

    await this.saveUser(user)
    return user
  }

  // Register new passkey for user
  async registerPasskey(
    userId: string,
    passkeyName: string,
    authenticatorAttachment: 'platform' | 'cross-platform' = 'platform'
  ): Promise<PasskeyCredential> {
    if (!this.db) throw new Error('Database not initialized')

    const user = await this.getUserById(userId)
    if (!user) {
      throw new Error('User not found')
    }

    try {
      // Generate challenge
      const challenge = this.generateChallenge()

      // Create credential creation options
      const credentialCreationOptions: CredentialCreationOptions = {
        challenge: this.base64URLToArrayBuffer(challenge),
        rp: {
          name: "Passkeys Manager",
          id: window.location.hostname
        },
        user: {
          id: this.base64URLToArrayBuffer(user.id),
          name: user.username,
          displayName: user.displayName
        },
        pubKeyCredParams: [
          { alg: -7, type: "public-key" },   // ES256
          { alg: -257, type: "public-key" },  // RS256
          { alg: -8, type: "public-key" },    // Ed25519
        ],
        authenticatorSelection: {
          authenticatorAttachment,
          residentKey: 'required',
          userVerification: 'required'
        },
        extensions: {
          credProps: true,
          largeBlob: true
        },
        timeout: 60000,
        attestation: 'direct'
      }

      // Create credential
      const credential = await navigator.credentials.create({
        publicKey: credentialCreationOptions
      }) as PublicKeyCredential

      if (!credential) {
        throw new Error('Credential creation failed')
      }

      // Parse client data
      const clientDataJSON = JSON.parse(
        new TextDecoder().decode(credential.response.clientDataJSON)
      )

      // Extract authenticator info
      const authData = new Uint8Array(credential.response.authenticatorData)
      const flags = authData[32]
      const backupEligible = !!(flags & 0x08)
      const backupState = !!(flags & 0x10)

      // Create passkey record
      const passkey: PasskeyCredential = {
        id: this.arrayBufferToBase64URL(credential.rawId),
        name: passkeyName,
        createdAt: new Date(),
        deviceType: authenticatorAttachment,
        userHandle: user.id,
        publicKey: this.arrayBufferToBase64URL(credential.response.publicKey || new ArrayBuffer(0)),
        counter: 0,
        transports: clientDataJSON.transports || [],
        backupEligible,
        backupState
      }

      // Add passkey to user
      user.passkeys.push(passkey)
      await this.saveUser(user)

      console.log('Passkey registered successfully:', {
        name: passkeyName,
        id: passkey.id,
        deviceType: passkey.deviceType,
        backupEligible: passkey.backupEligible
      })

      return passkey

    } catch (error) {
      console.error('Passkey registration error:', error)
      throw new Error(`Passkey registration failed: ${error.message}`)
    }
  }

  // Authenticate user with passkey
  async authenticate(userHint?: string): Promise<{ user: UserAccount; credentialId: string }> {
    if (!this.db) throw new Error('Database not initialized')

    try {
      // Generate challenge
      const challenge = this.generateChallenge()

      // Get all available passkeys if no specific user hint
      let allowCredentials: PublicKeyCredentialDescriptor[] = []

      if (userHint) {
        const user = await this.getUserByUsername(userHint)
        if (user && user.passkeys.length > 0) {
          allowCredentials = user.passkeys.map(passkey => ({
            id: this.base64URLToArrayBuffer(passkey.id),
            type: 'public-key',
            transports: passkey.transports as AuthenticatorTransport[]
          }))
        }
      }

      // Create assertion options
      const assertionOptions: AssertionOptions = {
        challenge: this.base64URLToArrayBuffer(challenge),
        allowCredentials,
        userVerification: 'required',
        extensions: {
          largeBlob: true
        },
        timeout: 60000
      }

      // Get assertion
      const assertion = await navigator.credentials.get({
        publicKey: assertionOptions
      }) as PublicKeyCredential

      if (!assertion) {
        throw new Error('Authentication failed')
      }

      // Find user by credential ID
      const credentialId = this.arrayBufferToBase64URL(assertion.rawId)
      let authenticatedUser: UserAccount | null = null
      let matchedPasskey: PasskeyCredential | null = null

      // Search all users for matching credential
      for (const user of await this.getAllUsers()) {
        const passkey = user.passkeys.find(pk => pk.id === credentialId)
        if (passkey) {
          authenticatedUser = user
          matchedPasskey = passkey
          break
        }
      }

      if (!authenticatedUser || !matchedPasskey) {
        throw new Error('Invalid credential')
      }

      // Update last used timestamp
      matchedPasskey.lastUsedAt = new Date()
      authenticatedUser.lastLoginAt = new Date()
      await this.saveUser(authenticatedUser)

      console.log('Authentication successful:', {
        user: authenticatedUser.username,
        credentialId,
        passkeyName: matchedPasskey.name
      })

      return { user: authenticatedUser, credentialId }

    } catch (error) {
      console.error('Authentication error:', error)
      throw new Error(`Authentication failed: ${error.message}`)
    }
  }

  // List user's passkeys
  async listPasskeys(userId: string): Promise<PasskeyCredential[]> {
    const user = await this.getUserById(userId)
    return user ? user.passkeys : []
  }

  // Delete passkey
  async deletePasskey(userId: string, passkeyId: string): Promise<void> {
    const user = await this.getUserById(userId)
    if (!user) {
      throw new Error('User not found')
    }

    const passkeyIndex = user.passkeys.findIndex(pk => pk.id === passkeyId)
    if (passkeyIndex === -1) {
      throw new Error('Passkey not found')
    }

    // Remove passkey
    user.passkeys.splice(passkeyIndex, 1)
    await this.saveUser(user)
  }

  // Update passkey name
  async updatePasskeyName(userId: string, passkeyId: string, newName: string): Promise<void> {
    const user = await this.getUserById(userId)
    if (!user) {
      throw new Error('User not found')
    }

    const passkey = user.passkeys.find(pk => pk.id === passkeyId)
    if (!passkey) {
      throw new Error('Passkey not found')
    }

    passkey.name = newName
    await this.saveUser(user)
  }

  // Database operations
  private async saveUser(user: UserAccount): Promise<void> {
    if (!this.db) throw new Error('Database not initialized')

    return new Promise((resolve, reject) => {
      const transaction = this.db!.transaction([this.STORE_NAME], 'readwrite')
      const store = transaction.objectStore(this.STORE_NAME)
      const request = store.put(user)

      request.onsuccess = () => resolve()
      request.onerror = () => reject(request.error)
    })
  }

  private async getUserById(userId: string): Promise<UserAccount | null> {
    if (!this.db) throw new Error('Database not initialized')

    return new Promise((resolve, reject) => {
      const transaction = this.db!.transaction([this.STORE_NAME], 'readonly')
      const store = transaction.objectStore(this.STORE_NAME)
      const request = store.get(userId)

      request.onsuccess = () => resolve(request.result || null)
      request.onerror = () => reject(request.error)
    })
  }

  private async getUserByUsername(username: string): Promise<UserAccount | null> {
    if (!this.db) throw new Error('Database not initialized')

    return new Promise((resolve, reject) => {
      const transaction = this.db!.transaction([this.STORE_NAME], 'readonly')
      const store = transaction.objectStore(this.STORE_NAME)
      const index = store.index('username')
      const request = index.get(username)

      request.onsuccess = () => resolve(request.result || null)
      request.onerror = () => reject(request.error)
    })
  }

  private async getAllUsers(): Promise<UserAccount[]> {
    if (!this.db) throw new Error('Database not initialized')

    return new Promise((resolve, reject) => {
      const transaction = this.db!.transaction([this.STORE_NAME], 'readonly')
      const store = transaction.objectStore(this.STORE_NAME)
      const request = store.getAll()

      request.onsuccess = () => resolve(request.result || [])
      request.onerror = () => reject(request.error)
    })
  }

  // Export passkeys for backup
  async exportPasskeys(userId: string): Promise<string> {
    const user = await this.getUserById(userId)
    if (!user) {
      throw new Error('User not found')
    }

    // Create export data (excluding sensitive fields)
    const exportData = {
      user: {
        id: user.id,
        username: user.username,
        email: user.email,
        displayName: user.displayName
      },
      passkeys: user.passkeys.map(pk => ({
        id: pk.id,
        name: pk.name,
        createdAt: pk.createdAt,
        deviceType: pk.deviceType,
        transports: pk.transports,
        backupEligible: pk.backupEligible
      })),
      exportedAt: new Date().toISOString()
    }

    return JSON.stringify(exportData, null, 2)
  }

  // Check browser compatibility
  static checkCompatibility(): {
    supported: boolean
    platformAuthenticator: boolean
    conditionalUI: boolean
    largeBlob: boolean
  } {
    return {
      supported: !!(navigator.credentials && navigator.credentials.create && navigator.credentials.get),
      platformAuthenticator: !!(PublicKeyCredential as any).isUserVerifyingPlatformAuthenticatorAvailable,
      conditionalUI: !!(PublicKeyCredential as any).isConditionalMediationAvailable,
      largeBlob: 'publicKey' in PublicKeyCredential.prototype
    }
  }
}

// React Component Example
// import React, { useState, useEffect } from 'react'

// const PasskeysManager: React.FC = () => {
//   const [passkeysManager] = useState(() => new PasskeysManager())
//   const [currentUser, setCurrentUser] = useState<UserAccount | null>(null)
//   const [passkeys, setPasskeys] = useState<PasskeyCredential[]>([])
//   const [loading, setLoading] = useState(false)
//   const [error, setError] = useState<string | null>(null)

//   useEffect(() => {
//     const compatibility = PasskeysManager.checkCompatibility()
//     console.log('WebAuthn compatibility:', compatibility)
//   }, [])

//   const handleRegisterPasskey = async (name: string, deviceType: 'platform' | 'cross-platform') => {
//     if (!currentUser) return

//     setLoading(true)
//     setError(null)

//     try {
//       const passkey = await passkeysManager.registerPasskey(currentUser.id, name, deviceType)
//       setPasskeys(prev => [...prev, passkey])
//     } catch (err) {
//       setError(err.message)
//     } finally {
//       setLoading(false)
//     }
//   }

//   const handleAuthenticate = async (userHint?: string) => {
//     setLoading(true)
//     setError(null)

//     try {
//       const { user } = await passkeysManager.authenticate(userHint)
//       setCurrentUser(user)
//       const userPasskeys = await passkeysManager.listPasskeys(user.id)
//       setPasskeys(userPasskeys)
//     } catch (err) {
//       setError(err.message)
//     } finally {
//       setLoading(false)
//     }
//   }

//   return (
//     <div className="passkeys-manager">
//       {/* UI implementation here */}
//     </div>
//   )
// }

export default PasskeysManager

// WebAuthn MFA Integration - Enhanced Security with Multiple Factors
// Backup codes, recovery options, and enterprise features

interface MFAConfig {
  passkeysRequired: boolean
  backupCodesEnabled: boolean
  smsEnabled: boolean
  emailEnabled: boolean
  timeBasedOTPEnabled: boolean
  rememberDevice: boolean
  sessionTimeout: number
}

interface BackupCode {
  id: string
  code: string
  usedAt?: Date
  createdAt: Date
  expiresAt: Date
}

interface AuthSession {
  id: string
  userId: string
  deviceFingerprint: string
  createdAt: Date
  expiresAt: Date
  isTrusted: boolean
  lastUsedAt: Date
}

interface SecurityEvent {
  id: string
  userId: string
  type: 'login' | 'passkey_added' | 'passkey_removed' | 'mfa_enabled' | 'suspicious_activity'
  timestamp: Date
  ipAddress: string
  userAgent: string
  success: boolean
  details?: any
}

class WebAuthnMFAIntegration {
  private passkeysManager: PasskeysManager
  private config: MFAConfig
  private mfaSessions = new Map<string, AuthSession>()
  private securityEvents: SecurityEvent[] = []

  constructor(config: MFAConfig) {
    this.passkeysManager = new PasskeysManager()
    this.config = config
  }

  // Enhanced authentication with MFA
  async authenticateWithMFA(userHint?: string): Promise<{
    user: UserAccount
    requiresMFA: boolean
    mfaMethods: string[]
    sessionToken?: string
  }> {
    try {
      // First attempt WebAuthn authentication
      const { user, credentialId } = await this.passkeysManager.authenticate(userHint)

      // Check if additional MFA is required
      const requiresMFA = this.shouldRequireMFA(user)

      if (!requiresMFA) {
        // Create trusted session
        const sessionToken = await this.createTrustedSession(user)

        await this.logSecurityEvent(user.id, 'login', true, {
          method: 'passkey_only',
          credentialId
        })

        return {
          user,
          requiresMFA: false,
          mfaMethods: [],
          sessionToken
        }
      }

      // MFA required - return available methods
      const mfaMethods = this.getAvailableMFAMethods(user)

      await this.logSecurityEvent(user.id, 'login', false, {
        method: 'passkey',
        requiresMFA: true,
        credentialId
      })

      return {
        user,
        requiresMFA: true,
        mfaMethods,
        sessionToken: this.createTemporaryMFASession(user)
      }

    } catch (error) {
      // Log failed authentication attempt
      await this.logSecurityEvent('', 'login', false, {
        error: error.message,
        userHint
      })

      throw error
    }
  }

  // Complete MFA verification
  async completeMFA(
    tempSessionToken: string,
    mfaMethod: string,
    mfaData: any
  ): Promise<{ user: UserAccount; sessionToken: string }> {
    const tempSession = this.mfaSessions.get(tempSessionToken)
    if (!tempSession || tempSession.expiresAt < new Date()) {
      throw new Error('Invalid or expired MFA session')
    }

    const user = await this.passkeysManager['getUserById'](tempSession.userId)
    if (!user) {
      throw new Error('User not found')
    }

    let mfaVerified = false

    switch (mfaMethod) {
      case 'backup_code':
        mfaVerified = await this.verifyBackupCode(user.id, mfaData.code)
        break
      case 'totp':
        mfaVerified = await this.verifyTOTP(user.id, mfaData.token)
        break
      case 'sms':
        mfaVerified = await this.verifySMS(user.id, mfaData.code)
        break
      case 'email':
        mfaVerified = await this.verifyEmail(user.id, mfaData.code)
        break
      default:
        throw new Error('Unsupported MFA method')
    }

    if (!mfaVerified) {
      await this.logSecurityEvent(user.id, 'login', false, {
        mfaMethod,
        mfaData
      })
      throw new Error('MFA verification failed')
    }

    // Create trusted session
    const sessionToken = await this.createTrustedSession(user)

    // Clean up temporary session
    this.mfaSessions.delete(tempSessionToken)

    await this.logSecurityEvent(user.id, 'login', true, {
      mfaMethod,
      deviceTrusted: true
    })

    return { user, sessionToken }
  }

  // Generate backup codes
  async generateBackupCodes(userId: string, count: number = 10): Promise<BackupCode[]> {
    const user = await this.passkeysManager['getUserById'](userId)
    if (!user) {
      throw new Error('User not found')
    }

    const backupCodes: BackupCode[] = []
    const expiresAt = new Date()
    expiresAt.setFullYear(expiresAt.getFullYear() + 1) // Valid for 1 year

    for (let i = 0; i < count; i++) {
      const code = this.generateBackupCode()
      backupCodes.push({
        id: this.generateId(),
        code,
        createdAt: new Date(),
        expiresAt
      })
    }

    // Store backup codes (in production, encrypt these)
    await this.storeBackupCodes(userId, backupCodes)

    await this.logSecurityEvent(user.id, 'mfa_enabled', true, {
      type: 'backup_codes_generated',
      count
    })

    return backupCodes
  }

  // Setup TOTP (Time-based One-Time Password)
  async setupTOTP(userId: string): Promise<{
    secret: string
    qrCodeUrl: string
    backupCodes: BackupCode[]
  }> {
    const user = await this.passkeysManager['getUserById'](userId)
    if (!user) {
      throw new Error('User not found')
    }

    // Generate TOTP secret
    const secret = this.generateTOTPSecret()
    const issuer = encodeURIComponent('Passkeys Manager')
    const accountName = encodeURIComponent(user.email)
    const qrCodeUrl = `otpauth://totp/${issuer}:${accountName}?secret=${secret}&issuer=${issuer}`

    // Generate backup codes
    const backupCodes = await this.generateBackupCodes(userId)

    // Store TOTP secret (in production, encrypt this)
    await this.storeTOTPSecret(userId, secret)

    await this.logSecurityEvent(user.id, 'mfa_enabled', true, {
      type: 'totp_setup'
    })

    return { secret, qrCodeUrl, backupCodes }
  }

  // Verify TOTP token
  async verifyTOTP(userId: string, token: string): Promise<boolean> {
    const secret = await this.getTOTPSecret(userId)
    if (!secret) {
      return false
    }

    // Verify token (simplified - use proper TOTP library in production)
    const expectedToken = this.generateTOTPToken(secret)
    const isValid = token === expectedToken

    if (isValid) {
      await this.logSecurityEvent(userId, 'login', true, {
        mfaMethod: 'totp',
        tokenVerified: true
      })
    }

    return isValid
  }

  // Check if MFA is required
  private shouldRequireMFA(user: UserAccount): boolean {
    if (!this.config.passkeysRequired) return false

    // Always require MFA if user has it enabled
    if (user.mfaEnabled) return true

    // Require MFA for new devices or suspicious locations
    // This would include IP geolocation, device fingerprinting, etc.
    return this.isNewDevice() || this.isSuspiciousLocation()
  }

  // Get available MFA methods for user
  private getAvailableMFAMethods(user: UserAccount): string[] {
    const methods = []

    if (this.config.backupCodesEnabled) {
      methods.push('backup_code')
    }

    if (this.config.timeBasedOTPEnabled) {
      // Check if user has TOTP setup
      if (this.hasTOTPSetup(user.id)) {
        methods.push('totp')
      }
    }

    if (this.config.smsEnabled && user.email) {
      methods.push('sms')
    }

    if (this.config.emailEnabled && user.email) {
      methods.push('email')
    }

    return methods
  }

  // Create trusted session
  private async createTrustedSession(user: UserAccount): Promise<string> {
    const session: AuthSession = {
      id: this.generateId(),
      userId: user.id,
      deviceFingerprint: this.generateDeviceFingerprint(),
      createdAt: new Date(),
      expiresAt: new Date(Date.now() + this.config.sessionTimeout),
      isTrusted: true,
      lastUsedAt: new Date()
    }

    // Store session (in production, use secure session storage)
    await this.storeSession(session)

    return session.id
  }

  // Create temporary MFA session
  private createTemporaryMFASession(user: UserAccount): string {
    const session: AuthSession = {
      id: this.generateId(),
      userId: user.id,
      deviceFingerprint: this.generateDeviceFingerprint(),
      createdAt: new Date(),
      expiresAt: new Date(Date.now() + 10 * 60 * 1000), // 10 minutes
      isTrusted: false,
      lastUsedAt: new Date()
    }

    this.mfaSessions.set(session.id, session)

    return session.id
  }

  // Utility methods
  private generateBackupCode(): string {
    const characters = 'ABCDEFGHJKLMNPQRSTUVWXYZ23456789' // Remove confusing characters
    let code = ''
    for (let i = 0; i < 8; i++) {
      if (i > 0 && i % 4 === 0) code += '-'
      code += characters[Math.floor(Math.random() * characters.length)]
    }
    return code
  }

  private generateTOTPSecret(): string {
    const base32Chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567'
    let secret = ''
    for (let i = 0; i < 32; i++) {
      secret += base32Chars[Math.floor(Math.random() * base32Chars.length)]
    }
    return secret
  }

  private generateTOTPToken(secret: string): string {
    // Simplified TOTP generation - use proper library in production
    const timestamp = Math.floor(Date.now() / 30000) // 30-second intervals
    return (timestamp + secret.length).toString().slice(-6)
  }

  private generateDeviceFingerprint(): string {
    const canvas = document.createElement('canvas')
    const ctx = canvas.getContext('2d')
    if (ctx) {
      ctx.textBaseline = 'top'
      ctx.font = '14px Arial'
      ctx.fillText('Device fingerprint', 2, 2)
      return canvas.toDataURL().slice(-20)
    }
    return Math.random().toString(36).substring(2)
  }

  private generateId(): string {
    return Math.random().toString(36).substring(2) + Date.now().toString(36)
  }

  private isNewDevice(): boolean {
    // Implement device fingerprinting logic
    return Math.random() > 0.7 // 30% chance of new device for demo
  }

  private isSuspiciousLocation(): boolean {
    // Implement geolocation checking
    return Math.random() > 0.9 // 10% chance of suspicious location for demo
  }

  // Security logging
  private async logSecurityEvent(
    userId: string,
    type: SecurityEvent['type'],
    success: boolean,
    details?: any
  ): Promise<void> {
    const event: SecurityEvent = {
      id: this.generateId(),
      userId,
      type,
      timestamp: new Date(),
      ipAddress: '192.168.1.1', // Get from request in production
      userAgent: navigator.userAgent,
      success,
      details
    }

    this.securityEvents.push(event)

    // In production, store in secure logging system
    console.log('Security event:', event)

    // Alert on suspicious activity
    if (!success || type === 'suspicious_activity') {
      await this.alertSuspiciousActivity(event)
    }
  }

  private async alertSuspiciousActivity(event: SecurityEvent): Promise<void> {
    // Implement alert system (email, SMS, admin notification)
    console.warn('🚨 Suspicious activity detected:', event)
  }

  // Storage methods (implement with your preferred storage)
  private async storeBackupCodes(userId: string, codes: BackupCode[]): Promise<void> {
    // Implement secure storage
  }

  private async storeTOTPSecret(userId: string, secret: string): Promise<void> {
    // Implement secure storage
  }

  private async getTOTPSecret(userId: string): Promise<string | null> {
    // Implement secure retrieval
    return null
  }

  private async hasTOTPSetup(userId: string): Promise<boolean> {
    // Check if TOTP is configured for user
    return false
  }

  private async storeSession(session: AuthSession): Promise<void> {
    // Implement secure session storage
  }

  // Enterprise features
  async getSecurityReport(userId: string): Promise<{
    user: UserAccount
    recentEvents: SecurityEvent[]
    trustedDevices: AuthSession[]
    securityScore: number
    recommendations: string[]
  }> {
    const user = await this.passkeysManager['getUserById'](userId)
    if (!user) {
      throw new Error('User not found')
    }

    const recentEvents = this.securityEvents
      .filter(event => event.userId === userId)
      .sort((a, b) => b.timestamp.getTime() - a.timestamp.getTime())
      .slice(0, 50)

    const trustedDevices = Array.from(this.mfaSessions.values())
      .filter(session => session.userId === userId && session.isTrusted)

    const securityScore = this.calculateSecurityScore(user, recentEvents)
    const recommendations = this.generateSecurityRecommendations(user, securityScore)

    return {
      user,
      recentEvents,
      trustedDevices,
      securityScore,
      recommendations
    }
  }

  private calculateSecurityScore(user: UserAccount, events: SecurityEvent[]): number {
    let score = 50 // Base score

    // Add points for passkeys
    score += Math.min(user.passkeys.length * 10, 30)

    // Add points for MFA enabled
    if (user.mfaEnabled) score += 20

    // Subtract points for failed login attempts
    const failedLogins = events.filter(e => e.type === 'login' && !e.success).length
    score -= Math.min(failedLogins * 5, 20)

    return Math.max(0, Math.min(100, score))
  }

  private generateSecurityRecommendations(user: UserAccount, score: number): string[] {
    const recommendations = []

    if (user.passkeys.length === 0) {
      recommendations.push('Add at least one passkey for passwordless authentication')
    }

    if (user.passkeys.length === 1) {
      recommendations.push('Add a backup passkey for account recovery')
    }

    if (!user.mfaEnabled) {
      recommendations.push('Enable multi-factor authentication for enhanced security')
    }

    if (score < 70) {
      recommendations.push('Review recent security events for suspicious activity')
    }

    return recommendations
  }
}

// Usage Example
// const mfaConfig: MFAConfig = {
//   passkeysRequired: true,
//   backupCodesEnabled: true,
//   smsEnabled: true,
//   emailEnabled: true,
//   timeBasedOTPEnabled: true,
//   rememberDevice: true,
//   sessionTimeout: 24 * 60 * 60 * 1000 // 24 hours
// }
//
// const mfaIntegration = new WebAuthnMFAIntegration(mfaConfig)
//
// // Authenticate with MFA
// const authResult = await mfaIntegration.authenticateWithMFA('[email protected]')
// if (authResult.requiresMFA) {
//   // Show MFA options UI
//   console.log('Available MFA methods:', authResult.mfaMethods)
//
//   // Complete MFA (user enters backup code)
//   const finalResult = await mfaIntegration.completeMFA(
//     authResult.sessionToken!,
//     'backup_code',
//     { code: 'ABCD-1234-EFGH' }
//   )
//   console.log('Authentication complete:', finalResult)
// }

export default WebAuthnMFAIntegration